Image forming apparatus

ABSTRACT

An image forming apparatus includes a medium transport path that branches at a predetermined branching position and along which a medium is transported toward a stacking portion in a curved state; an opening-closing member capable of opening and closing, the opening-closing member opening so as to expose an inner section of an apparatus body in a region upstream of the branching position in a medium transporting direction; and a guiding member having a guide surface that serves as a first guide surface of the medium transport path at a concave side of the medium transport path, the guiding member being supported such that the guiding member is rotatable between a guiding orientation in which the guiding member guides the medium and an opening orientation to which the guiding member rotates from the guiding orientation to open the guide surface of the guiding member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2015-124434 filed Jun. 22, 2015.

BACKGROUND Technical Background

The present invention relates to an image forming apparatus.

SUMMARY

According to an aspect of the invention, there is provided an image forming apparatus including a medium transport path that branches at a predetermined branching position and along which a medium is transported toward a stacking portion in a curved state; an opening-closing member capable of opening and closing, the opening-closing member opening so as to expose an inner section of an apparatus body in a region upstream of the branching position in a medium transporting direction; and a guiding member having a guide surface that serves as a first guide surface of the medium transport path at a concave side of the medium transport path, the guiding member being supported such that the guiding member is rotatable between a guiding orientation in which the guiding member guides the medium and an opening orientation to which the guiding member rotates from the guiding orientation to open the guide surface of the guiding member.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein:

FIG. 1 is a sectional schematic diagram illustrating the inner structure of an image forming apparatus;

FIG. 2 is a sectional schematic diagram illustrating a sheet transport path of a sheet transport device;

FIG. 3 is a sectional schematic diagram illustrating the sheet transport path of the sheet transport device in a state in which a guiding member is in an opening orientation;

FIG. 4 is a perspective view illustrating the inner structure of the sheet transport device in a state in which the guiding member is in a guiding orientation;

FIG. 5 is a perspective view illustrating the inner structure of the sheet transport device in a state in which the guiding member is in the opening orientation;

FIG. 6 is a sectional schematic diagram illustrating the manner in which an opening-closing member is closed while the guiding member is engaged with an apparatus body;

FIG. 7 is a sectional schematic diagram illustrating the manner in which the opening-closing member is closed while the guiding member is not engaged with the apparatus body;

FIG. 8 is a sectional schematic diagram illustrating the state in which the guiding member and the opening-closing member are engaged with the apparatus body; and

FIG. 9 is a sectional schematic diagram illustrating the image forming apparatus in which the opening-closing member is opened and the guiding member is in the opening orientation.

DETAILED DESCRIPTION

The present invention will be explained in further detail by describing an exemplary embodiment and examples with reference to the drawings. However, the present invention is not limited to the exemplary embodiment and examples.

It is to be noted that the drawings referred to in the following description are schematic, and that dimensional ratios, for example, are not equal to the actual dimensional ratios. Components other than those needed to be explained to facilitate understanding are omitted as appropriate in the drawings.

1. Overall Structure and Operation of Image Forming Apparatus

FIG. 1 is a vertical sectional view illustrating the inner structure of an image forming apparatus 1.

The overall structure and operation of the image forming apparatus 1 will be described with reference to the drawings.

The image forming apparatus 1 includes a control device 10, a sheet feeding device 20, photoconductor units 30, developing devices 40, a transfer device 50, a fixing device 60, and a sheet transport device 70. A paper output tray unit T1, which receives paper sheets having images recorded thereon, is provided on an upper surface (Z-direction-side surface) of the image forming apparatus 1.

The control device 10 includes a controller 11 that controls the operation of the image forming apparatus 1, an image processing unit 12 that performs an operation controlled by the controller 11, and a power supply device 13. The power supply device 13 applies a voltage to devices including the photoconductor units 30, the developing devices 40, and the transfer device 50.

The image processing unit 12 converts print information input thereto from an external information transmission device (for example, a personal computer) into image information used to form a latent image, and outputs a drive signal to an exposure device at a preset timing.

A sheet feeding device 20 that contains a stack of paper sheets P, which serve as media, is provided at the bottom of the image forming apparatus 1. The paper sheets P, which are positioned in a width direction by a regulating plate (not shown), are drawn out one at a time in the forward direction (−X direction) by a sheet drawing unit 22.

The paper sheets P drawn out by the sheet drawing unit 22 is transported along a sheet transport path to a nip portion of a registration roller pair 23.

The photoconductor units 30 include photoconductor drums 31 that are arranged next to each other in a region above (on the Z-direction side of) the sheet feeding device 20. Yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed on the photoconductor drums 31 by the respective developing devices 40.

The toner images of the respective colors formed on the photoconductor drums 31 of the photoconductor units 30 are successively electrostatically transferred onto an intermediate transfer belt 51, which is included in the transfer device 50, in a first transfer process, so that a superposed toner image in which the toners of the respective colors are superposed is formed. The superposed toner image formed on the intermediate transfer belt 51 is transferred by a second transfer roller 52 onto a paper sheet P that has been transported from the registration roller pair 23 and guided by a transport guide.

The fixing device 60 includes a fixing nip portion (fixing region) in a region in which a pair of modules, which are a heating module 61 and a pressing module 62, are pressed against each other.

The paper sheet P onto which the toner image has been transferred by the transfer device 50 is transported to the fixing nip portion of the fixing device 60 along a transport guide 53 while the toner image is not fixed. The pair of modules, which are the heating module 61 and the pressing module 62, apply heat and pressure to the toner image to fix the toner image.

The paper sheet P on which the fixed toner image is formed is guided by a first transport path S1 of the sheet transport device 70 and output to the paper output tray unit T1 on the upper surface of the image forming apparatus 1 from a first output roller pair 80. When the paper sheet P is to be reversed for duplex printing or output in such a state that the image-recorded surface faces upward, the transporting direction is switched to a direction toward a second transport path S2 by a first switching gate G1.

The second transport path S2 extends to a second switching gate G2 that switches between a face-down paper output mode in which the paper sheet P is output from a second output roller pair 81 to a paper output tray T2 while the image-recorded surface faces downward, and a face-up paper output mode in which the paper sheet P is output from a third output roller pair 82 to a paper output tray T3 while the image-recorded surface faces upward.

2. Structure and Operation of Sheet Transport Device

FIG. 2 is a sectional schematic diagram illustrating a sheet transport path of the sheet transport device 70. FIG. 3 is a sectional schematic diagram illustrating the sheet transport path of the sheet transport device 70 in a state in which a guiding member 75 is in an opening orientation.

The structure and sheet transporting operation of the sheet transport device 70 included in the image forming apparatus 1 will be described with reference to the drawings.

2.1. Structure of Sheet Transport Unit

As illustrated in FIG. 2, the sheet transport device 70 includes guides 71 a and 71 b, transport roller pairs 72, 73, and 74, the first switching gate G1, the second switching gate G2, the first output roller pair 80, the second output roller pair 81, the third output roller pair 82, and the guiding member 75.

The guides 71 a and 71 b, which are located downstream of the fixing nip portion of the fixing device 60, guide the paper sheet P to which the toner image is fixed to the transport roller pair 72. The first transport path S1, which extends from the transport roller pair 72 to the first output roller pair 80, is defined by the first switching gate G1.

The first switching gate G1 is supported so as to be rotatable, as shown by the arrow in FIG. 2, between a first position for guiding the paper sheet P to the first output roller pair 80 and a second position for guiding the paper sheet P to the transport roller pair 73.

In a state in which the first switching gate G1 is at the first position for guiding the paper sheet P to the first output roller pair 80, the first transport path S1, which extends from the transport roller pair 72 to the first output roller pair 80, is curved so as to suppress an increase in the height of the apparatus.

The second transport path S2 is provided downstream of the transport roller pair 72 in the sheet transporting direction, and the second switching gate G2 is located at a branching point of the second transport path S2.

The second switching gate G2 connects the second transport path S2 to a third transport path S3 that guides the paper sheet P to the second output roller pair 81, or to a fourth transport path S4 that guides the paper sheet P to the third output roller pair 82, as shown by the arrow in FIG. 2.

The paper output tray T2 receives the paper sheet P in a state in which the image-recorded surface faces downward (face-down state). The paper output tray T3 receives the paper sheet P in a state in which the image-recorded surface faces upward (face-up state).

2.2. Formation of Sheet Transport Path

The second transport path S2 is defined by a portion of a sheet guide surface 75 a of the guiding member 75 and a guide 76 that serves as one of sheet guide surfaces of the third transport path S3. The third transport path S3 is defined by the guide 76 and a first guide surface G2 a of the second switching gate G2.

A portion of the fourth transport path S4 located upstream of the transport roller pair 74 in the sheet transporting direction is defined by the sheet guide surface 75 a of the guiding member 75 at a concave side, and by a second guide surface G2 b of the second switching gate G2 at a convex side. A portion of the fourth transport path S4 located downstream of the transport roller pair 74 in the sheet transporting direction is defined by the sheet guide surface 75 a and the guide 77.

The entire body of the guiding member 75 is curved in sectional view and includes pinch rollers 73 b and 74 b urged so as to project from the sheet guide surface 75 a, which defines the concave sides of the second transport path S2 and the fourth transport path S4.

The pinch roller 73 b is pressed against a drive roller 73 a, which belongs to the transport roller pair 73, in a rotatable manner, and transports the paper sheet P along the second transport path S2. The pinch roller 74 b is pressed against a drive roller 74 a, which belongs to the transport roller pair 74, in a rotatable manner, and transports the paper sheet P from the second transport path S2 to the fourth transport path S4.

2.3. Sheet-Transport-Path Opening Operation

As illustrated in FIG. 3, the guiding member 75 rotates around a support shaft 75 b owing to its own weight so as to open the second transport path S2 and the fourth transport path S4.

The support shaft 75 b, which serves as the center of rotation, is at a position separated from the branching position toward the downstream side in the sheet transporting direction. When the guiding member 75 is rotated to the opening orientation, each of the second transport path S2 and the fourth transport path S4 is opened such that the distance between the guide surfaces thereof increases, as shown by the arrow in FIG. 3.

3. Jammed-Paper-Sheet Removing Operation

FIG. 4 is a perspective view illustrating the inner structure of the sheet transport device 70 in a state in which the guiding member 75 is in the guiding orientation. FIG. 5 is a perspective view illustrating the inner structure of the sheet transport device 70 in a state in which the guiding member 75 is in the opening orientation. FIG. 6 is a sectional schematic diagram illustrating the manner in which an opening-closing member 100 is closed while the guiding member 75 is engaged with an apparatus body. FIG. 7 is a sectional schematic diagram illustrating the manner in which the opening-closing member 100 is closed while the guiding member 75 is not engaged with the apparatus body. FIG. 8 is a sectional schematic diagram illustrating the state in which the guiding member 75 and the opening-closing member 100 are engaged with the apparatus body. FIG. 9 is a sectional schematic diagram illustrating the state in which the opening-closing member 100 is opened and the guiding member 75 is in the opening orientation.

The jammed-paper-sheet removing operation of the image forming apparatus 1 will be described below with reference to the drawings.

3.1. Jammed-Paper-Sheet Removing Operation

As illustrated in FIG. 4, when the opening-closing member 100 of the apparatus body is opened so that the inner section of the apparatus body is exposed, the sheet transport device 70, which is located downstream of the fixing device 60, is exposed while the paper output tray T3 is fixed to the apparatus body.

The opening-closing member 100 includes an engagement portion 102 that rotates in response to an operation of an operation lever 101. The engagement portion 102 has an engagement recess 102 a that engages with a boss 110, which serves as an engagement portion provided on the apparatus body, so as to maintain the sheet transport path that extends from the sheet drawing unit 22 of the sheet feeding device 20 to the transport guide 53 via the registration roller pair 23 and the second transfer roller 52.

The guiding member 75 is retained in the guiding orientation such that the downstream portion thereof in the sheet transporting direction is rotatably supported on the apparatus body by the support shaft 75 b, and such that an engagement portion 78 thereof provided at the upstream side in the sheet transporting direction is engaged with a boss 120, which also serves as an engagement portion provided on the apparatus body.

When an operation lever 79 of the guiding member 75 is operated while the sheet transport device 70 is exposed, as illustrated in FIG. 5, the engagement portion 78 is released from the boss 120 in response to the operation of the operation lever 79, and the guiding member 75 is rotated to the opening orientation.

When the guiding member 75 is in the opening orientation, the second transport path S2 and the fourth transport path S4 are opened such that the guide 76 of the third transport path S3, the second switching gate G2, and the guide 77 of the fourth transport path S4 are exposed, thereby allowing the jammed paper sheet to be removed.

The support shaft 75 b, which serves as the center of rotation of the guiding member 75, is at a position separated from the branching position toward the downstream side in the sheet transporting direction. When the guiding member 75 is rotated to the opening orientation, each of the second transport path S2 and the fourth transport path S4 is opened such that the distance between the guide surfaces thereof is increased.

Thus, the user may easily remove the jammed paper sheet.

When the sheet transport path of the sheet transport device 70 is to be exposed, the user operates the operation lever 101 of the opening-closing member 100 without moving the paper output tray T3 on which the paper sheets P are stacked, so that the sheet transport device 70 is exposed. Then, the user operates the operation lever 79 of the guiding member 75. Accordingly, the sheet transport path of the sheet transport device 70 opens owing to its own weight (see FIG. 9).

Thus, the jammed-paper-sheet removing operation to be performed by the user is clear, and the risk of misoperation may be reduced.

Since the sheet transport device 70 may be exposed without moving the paper output tray T3 on which the paper sheets P are stacked, it is not necessary to provide a mechanism for preventing the paper sheets stacked on the paper output tray T3 from falling. Accordingly, the size of the apparatus body may be reduced.

3.2. Sheet-Transport-Device Closing Operation

FIG. 6 illustrates the manner in which the opening-closing member 100 is closed while the guiding member 75 is engaged with the apparatus body. In the image forming apparatus 1 according to the present exemplary embodiment, the guiding member 75 that defines the sheet transport path of the sheet transport device 70 is retained in the guiding orientation when the engagement portion 78 is engaged with the boss 120, which serves as the engagement portion provided on the apparatus body.

When the opening-closing member 100 that has been opened so that the inner section of the apparatus body is exposed is rotated in the closing direction (see the arrow in FIG. 6), the engagement recess 102 a in the engagement portion 102 engages with the boss 110, which serves as the engagement portion provided on the apparatus body, so as to establish the state in which the sheet transport path that extends from the sheet drawing unit 22 to the transport guide 53 via the registration roller pair 23 and the second transfer roller 52 is maintained.

Accordingly, the reaction force against the contact pressure applied to the pinch rollers 73 b and 74 b of the transport roller pairs 73 and 74 included in the sheet transport device 70 is received by the engagement portion 78 of the guiding member 75, and is not applied to the opening-closing member 100. Thus, the operation of closing the opening-closing member 100 may be easily performed independently of the operation of closing the guiding member 75.

FIG. 7 illustrates the manner in which the opening-closing member 100 is closed while the guiding member 75 is not engaged with the apparatus body.

The opening-closing member 100 includes a pushing rib 103 that projects from an inner surface of the opening-closing member 100. During the operation of closing the opening-closing member 100, the pushing rib 103 moves toward the sheet transport device 70 and comes into contact with an inclined surface 78 a formed on the engagement portion 78 of the guiding member 75.

When the operation of closing the opening-closing member 100 is performed while the pushing rib 103 of the opening-closing member 100 is in contact with the inclined surface 78 a formed on the engagement portion 78 of the guiding member 75, the pushing rib 103 moves as shown by the arrow R1 in FIG. 7 while rotating the engagement portion 78 as shown by the arrow R2 in FIG. 7, so that the engagement portion 78 engages with the boss 120 provided on the apparatus body.

When the opening-closing member 100 is further rotated in the closing direction, the engagement recess 102 a in the engagement portion 102 engages with the boss 110, which serves as the engagement portion provided on the apparatus body, so that the inner section of the apparatus body is closed in such a state that the sheet transport path that extends from the sheet drawing unit 22 to the transport guide 53 via the registration roller pair 23 and the second transfer roller 52 is maintained.

As a result, even when the operation of closing the opening-closing member 100 is performed while the guiding member 75 is not engaged with the apparatus body, the guiding member 75 of the sheet transport device 70 may be reliably engaged with the boss 120, which serves as the engagement portion provided on the apparatus body, and retained in the guiding orientation.

FIG. 8 illustrates the state in which the guiding member 75 and the opening-closing member 100 are engaged with the apparatus body.

In the image forming apparatus 1 according to the present exemplary embodiment, the engagement portion 78 of the guiding member 75 included in the sheet transport device 70 engages with the boss 120 on the apparatus body, so that the guiding member 75 is retained in the guiding orientation.

In addition, the engagement portion 102 of the opening-closing member 100 engages with the boss 110 on the apparatus body, so that the inner section of the apparatus body is closed in such a state that the sheet transport path that extends from the sheet drawing unit 22 to the transport guide 53 via the registration roller pair 23 and the second transfer roller 52 is maintained.

Accordingly, the reaction force against the contact pressure applied to the pinch rollers 73 b and 74 b of the transport roller pairs 73 and 74 included in the sheet transport device 70 is received by the engagement portion 78 of the guiding member 75, and is not applied to the opening-closing member 100, so that deformation of the opening-closing member 100 may be suppressed.

The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 

1. An image forming apparatus comprising: a medium transport path that branches at a predetermined branching position and along which a medium is transported toward a stacking portion in a curved state; an opening-closing member capable of opening and closing, the opening-closing member opening so as to expose an inner section of an apparatus body in a region upstream of the branching position in a medium transporting direction; and a guiding member including a first roller and a second roller spaced apart from each other along the medium transporting direction, the guiding member having a guide surface at least between the first roller and the second roller, the guide surface serving as a first guide surface of the medium transport path, the guiding member being supported such that the guiding member is rotatable between a guiding orientation in which the guiding member guides the medium and an opening orientation to which the guiding member rotates from the guiding orientation to open the guide surface of the guiding member.
 2. The image forming apparatus according to claim 1, wherein a center of rotation of the guiding member is at a position separated from the branching position toward a downstream side in the medium transporting direction along the medium transport path, and wherein a distance between the first guide surface and a second guide surface, which faces the first guide surface, of the medium transport path increases when the guiding member rotates to the opening orientation.
 3. The image forming apparatus according to claim 1, wherein the guiding member rotates from the guiding orientation to the opening orientation owing to a weight of the guiding member.
 4. The image forming apparatus according to claim 1, further comprising: an engagement portion provided on the apparatus body; an engagement portion provided on the guiding member and capable of engaging with the engagement portion on the apparatus body; and a contact portion that is provided on the opening-closing member and that moves relative to the engagement portion on the guiding member while being in contact with a contact portion of the engagement portion on the guiding member when the opening-closing member moves from an opened position to a closed portion.
 5. The image forming apparatus according to claim 4, wherein the guiding member includes a holding portion that disengages the engagement portion on the guiding member and the engagement portion on the apparatus body from each other.
 6. The image forming apparatus according to claim 1, wherein the stacking portion is fixed to the apparatus body.
 7. The image forming apparatus according to claim 1, wherein the first guide surface defines a curved surface of the medium transport path.
 8. The image forming apparatus according to claim 1, wherein in the guiding orientation, each of the first roller and the second roller of the guiding member contacts a corresponding roller of the apparatus to form a transport roller pair therebetween. 